Département de chimie moléculaire

Ruthenium(II) polyazaarom. complexes have gained interest in recent decades as biomol. tools, esp. in the development of new phototherapeutic agents. These light emissive Ru complexes based on $π$-deficient ligands were first designed to allow a photo-induced electron transfer (PET) with the guanine base in DNA since their 3MLCT state is highly photo-oxidizing. Later the field of research was extended to proteins with the highlighting of a PET process with the tryptophan residue. This paper reports the kinetics of the luminescence quenching of [Ru(TAP)2phen]2+ by several selected peptide sequences contg. at least one tryptophan residue. By using a peptide library we highlight the important parameters influencing the kinetics of the photo-electron transfer process, such as the net electrostatic charge and the no. of tryptophan residues. The best peptide candidates were selected to study the formation of photo-products by MALDI-ToF mass spectrometry. A high photoreactivity of the [Ru(TAP)2phen]2+ complex was obsd. and multiple photoadducts were characterized, among them inter-peptidic adducts as well as intra-peptidic adducts. [on SciFinder(R)]